I see pus sy was edited.
Why're you guys so afraid of a little pus sy?

 

randedge, congrats on the evo one, i know a couple ppl who were interested in it, good buy... keep us posted and lemme know if u ever show up to a Lancer meet...

 

Randage, congratulations on a great find.. There are two types of rear LSD. The GSR comes with VCU which is clutch pack style. Same as the front would be if you have that option. The RS came with gear type LSD in the rear. Also known as torsen style.
If you want to determine if you have the front try spinning a front wheel. If the other front spins same direction you have LSD. Heres a pic of my new white one. I have been buying the evo3 conversion parts off e-bay for three years. I finally found all the peices so soon one of my cars will get the evo3 look. cars look awesome in white.

 

Lets end the mis-information in this thread right here:

Viscous diff's are an LSD. Viscous refers to the type of torque transfer unit that is used. Search it on google and read about how it works, as I dont want to explain it. Bottom line is it IS an LSD (limited slip differential)

The stock diff in the front of any Evo is an OPEN differentail, it does not have any torque transfering capabilities when a wheel is slipping. It was an option for the Evo 1-3 for a viscous front LSD. An option for the RS from the Evo 4-on was a torque-adaptive helical gear limited slip front differential (Torsen).

The center diff of every single Evo (without ACD) is a Viscous type LSD. This is essentially an Open Diff with a Viscous Coupling Unit attached to it, giving it the torque transfering capabilities of an LSD. A Viscous LSD is NOT a gear type or clutch type LSD.

I am not fully familliar with the earlier evos (Im told the rear Diff's were clutch type in the RS, viscous in the GSR), but from the Evo 4 to current Evo's that were not sold in the USA, they had clutch-type rear LSD's in the RS's, or AYC in the GSR's. AYC is an active LSD. In regular AYC form it can transfer up to 75% of the torque to the tire with more grip. S-AYC can do something like 80-85%.

US evo 8/9's were clutch type rears.

94awdcoupe is partly correct about checking for a front LSD. if it were a clutch type LSD, it will spin the same way as the wheel you are spinning right away. If it were a Viscous LSD, it will spin opposite for a second or two, then switch, and spin the same way. (read about viscous LSD's and you will know why). torsen style LSD's will spin the opposite way no matter what, because a torsen style LSD can only transfer torque until one wheel completely looses grip. then it essentially operates as an open diff once that happens. This is why it is mostly only used in the front of AWD cars or FWD cars.

 

Here is a basic link on how VCU's work:

http://en.wikipedia.org/wiki/Viscous_coupling_unit

 

damn i want a Evo I w/ RHD

 

Nice!!!

 

Nice! Where do you find these cars in such good shape?

 

I watch e-bay like a hawk.

Fatheroft, you are wrong about the early evo optional front diff being viscous. It is an amazing sealed clutch pack. 48 clutch plates. sealed meaning it doesnt share fluid with the tranny. I think that list is wrong about the rear though. I think the rs came with the VCU and the GSR came with torsen style.

 

Torsen never came in the rear of an evo, its not beneficial in any way to put one in the rear. Its good for a center if its a track car, and great for the front of any AWD/FWD car. Torsen's cannot transfer torque at all when a wheel is actually slipping, so it does not work well in the rear.

I had an evo 0(GVR-4 RS)/1 gearbox in my galant VR-4 and it had a viscous front LSD. Wether or not thats the "sealed" version your speaking of I dunno. I know I was the only on in the country that was known to have it in a usdm GVR-4 though. And, it made the car a BLAST to drive around a roadcourse, I cant explain the difference it made pulling out of a corner apex...

But technically, your description of a "sealed clutch type" LSD is exactly what a Viscous LSD is. So therefore, I almost guarantee its a viscous LSD youre speaking of. Especially since the limited info I had about the front LSD my old tranny had told me it was a very good and beefy front LSD.

Granted, I could be wrong about the evo 1/3. But I assure you, I know what a evo 4+ has in it

 

I own two evo1 cars and build trannies for a living. I am pretty sure I know what I am taking about. Actually the front diff is viscous. It has 48 plates that resist turning in a viscous fluid. I incorrectly called them clutch plates. There is no friction material on them. Just thin metal discs in a 500wt oil. I took one apart to learn. I suspect the center viscous is similar construction, but they are welded shut. You would have to cut one open to see inside. I have not seen the gvr rs tranny so I dont know what kind it came with. But there is a jdm front torsen diff that fits in the awd tranny. I have one of those as well. Its a gear type just like the one in an evo4-8 rs t-case.

viscous and clutch diffs work the same. the torsen works differently. clutch type diffs work when one wheel goes off the ground. torsen ones need both wheels on the ground. there is no reason a torsen wouldnt work for the rear. torsen diffs are cheaper to manufacture and live longer than clutch type diffs.

 

So, im wrong but im right? Not to butt heads here, but I also know what im talking about. As I stated before, from the factory, the option was only a viscous front LSD for an evo 1/2/3. There is a ralliart torsen front for these old style boxes. that might be what you have, in which you are one lucky person, I only know one other person with one of those. select dealers are said to have installed these as an "aftermarket option" in JP.

A torsen/helical diff on the rear of a car would only be beneficial in the rear if you had so much grip, that you wouldn't ever overcome it. And actually, some race-prepped cars do run torsen rears, but its rare to see. You need to rear through my posts thouroghly, as you outlined basically exactly what I said earlier, with some mi nor details still wrong.

As for the evo 4-9, ALL non-ACD center differentials are Viscous, not gear type/torsen/helical. And there was never a stock torsen/helical rear. Only for the front in RS's and as an option in 5/6's. I know the 4/5/6 better than the older Evos, as I drive this:

 

I love these old evo's.

 

my statement about evo4 diff is correct. The front diff of evo4-9 lives in the t-case. sounds like you think it lives in the tranny like evo1-3 cars. The evo 4-9 front diff is torsen gear type. If the car is acd equiped it will come with this same torsen diff . the center diff lives in the tranny on all evos. but the viscous coupler lives in the t-case for evo 4-9. If the t-case is acd the coupler is replaced with ACD clutch pack. my experience is not from reading threads but actually handling and rebuilding the parts. this will be my last post on this since you dont like your details being corrected. off topic as well.

 

The ABS module is located on the left front side of the engine bay (right side if you are facing the car). It sits in front of the wheel but you can see see it when looking in the engine bay.